1. Field of the Invention
The present invention relates to ether-ketone polymers, particularly to hyperbranched ether-ketone polymers and a new technique to synthesize them from the mixtures of a trifunctional carboxylic acid (A3) and a difunctional bis(arylether) (B2) monomers in appropriate stoichiometric ratios.
2. Description of the Related Art
Non-traditional macromolecules such as dendrimers and hyperbranched polymers are attracting a considerable amount of attention primarily because of their distinctly different properties compared to their linear counterparts. For example, they have better solubility compared to their linear analogs. Although dendrimers have precisely controlled structure and unique properties, their preparations generally involve tedious, multi-step sequences that are not practical in mass production. Synthesis of a hyperbranched polymer, on the other hand, is a one-pot process. Large quantities of hyperbranched polymers can be easily produced from ABx (x≧2) monomers. In addition, there are important characteristics such as low viscosity and dependence of the physical properties on the nature and number of endgroups such as solubility, glass-transition etc. are quite similar between hyperbranched polymers and dendrimers. Therefore, hyperbranched polymers are better suited for many practical applications. Perhaps an important disadvantage associated with a particular hyperbranched polymer is that the synthesis of its ABx monomer often time still involves several reaction sequences from commercially available starting materials.
To be more cost-competitive, a promising approach entails direct syntheses of hyperbranched polymers for high temperature applications from commercially available A3 and B2 or A2 and B3. Although a number of hyperbranched polymers have been synthesized via either an A3+B2 or an A2+B3 polycondensation process, these processes did present some difficulty in controlling polycondensation reaction due to premature gelation. Thus, an important key to the success of such an approach is to be able to: (a) control the reaction conditions such as the monomer concentrations and their time-dependent reaction ratio; and (b) stop the reaction before the gelation starts.